Piston expanding apparatus



. Dec. 29, 1942. D. RUBIN 2,306,756

I PISTON EXPANDING APPARATUS Original Filed Dec. 1, 1937 3 sheetksheetl1 i mm Q m i m a KIIPLIJIIIIWP 0 Dec! 29, 1942. RUBlN 2,306,756

PISTON EXPANDING APPARATUS I Original Filed Dec. 1, 1937 S'Sheets-Sheet2 un 1 llll H I I "K I m VENTOB David Tiub/n ArronA/Em Patented Dec. 29,1942 PISTON EXPANDING APPARATUS David Rubin, Scranton, Pa., assignor toScranton Industrial Development Company, Scranton, vPa., a corporationof Delaware Original application December 1, 1937, Serial No.

Divided and this application August 29, 1939, Serial No. 292,499

1 Claim.

This invention relates generally to devices for decreasing the clearanceof pistons in the cylinders of internal combustion motors and moreparticularly to machines for expanding the pistons of such motors.

This application is a division of my application Serial'Number 177,569,filed" December 1, 1937, now Patent 2,174,217, dated September 26, 1939,and a continuation-in-part of my application Serial Number 118,964,filed January 4, 1937.

Internal combustion engines after a certain amount of use, losecompression and power owing to the fact that the piston rings, cylinderwall and piston skirt become worn down. The cylinder may be rebored andnew rings and piston installed, but it ischeaper to replace the wornrings with new ones and use the old piston. The old piston, because ofits relatively reduced-diameter, oscillates about the piston pin andbetween the cylinder walls giving rise to what is known as "piston slap.It is well known to insert a resilient expansive device within thepiston skirt to enlarge the same, but this is unsatisfactory for manyreasons, including the facts that insufflcient enlargement is obtainedand the characteristics of the piston are altered.

Inasmuch as the new piston rings provide increased compression, 1 havefound that if the piston skirt is expanded transversely of the pistonpin, piston slap is removed and oil consumption is considerably reduced.I have also found that if instead of being expanded, the piston skirt isovalized (a reduction of the skirt diameter, longitudinally of thepiston pin and a corresponding increase in piston skirt diametertransversely of the pin) an improved motor f performance is obtained.Where the piston skirt is slotted a combination of expanding andovalizing is very satisfactory.

.While it has been proposed-to expand piston skirts byhammering orpeening them to an expanded shape, this has been unsatisfactory in thatinsuflicient expansion is produced and the peening causes the metal tocrystallize and become brittle.

The present invention contemplates the physi cal expansion of the pistonskirt while the same is in a heated and annealed condition. After thestretching operation is completed, the piston is retempered so that itsoriginal metallic condition is restored but the new shape is retained.The metal heating and treatment varies with the metallic composition ofthe piston.

ure 1;

tons, such method involving certain steps of heating, stretching, andcooling. The invention disclosed and claimed in the'present applicationrelates more especially to apparatus for expanding pistons, e. g., inaccordance with the method disclosed in my aforementioned patent. Itwill be understood, however, that apparatus embodying my presentinvention is not restricted in use to the practice of the particularmethod referred to.

The main object of the present invention is the provision of structurewhereby a simple, efficient and inexpensive device accurately expandspistons of various types under close control.

Another object is to provide apparatus of the character referred toincluding a measuring device so correlatively arranged with respect tothe piston forcing or expanding parts as to be conveniently movable tooperating position and to be capable of indicating accurately the amountof expansion effected. v

Other objects will become apparent from a reading of the followingdescription, the appended claim, and the accompanying drawings, inwhich:

Figure l is a fragmentary plan view of one preferred embodiment of theinvention;

Figure 2 is a fragmentary elevational view of Figure 1;

Figure 3 is an enlarged fragmentary elevational view of the front of themachine shown in Fig- Figure 4 is an elevational front view of analternate type of piston expanding peg;

Figure 5 is a sectional view of Figure 4 as seen from the plane 5-5thereon;

Figure 6 is a bottom view of the moving piston peg shown on Figure 3 asseen from the plane 3-3 thereon;

Figure 7 is a top plan view of a further preferred embodimentgof theinvention;

Figure 8 is a view in side elevation of the embodiment shown in Figure7;

Figure 9 is a longitudinal vertical sectional view taken on the line 9-9of Figure 7;

' Figure 10 is a vertical cross sectional view taken on the line Ill-l0of Figure 7; and

Figure 11 is a detail perspective view of a piston-engaging abutment.

Form shown in Figures 1 to 6 inclusive l2 and I3 respectively and theside walls l4 and I5 may be sufficiently extended downwardly to enclosethe heating and tempering ovens (not shown) for treating the pistonsbefore and after stretching.

The stretching or expanding assembly, generally indicated by numeral I6,is composed essentially of a stationary arm l1 and a moving arm orcarrier l8 upon which are detachably mounted a stationary pistonexpansion abutment or peg I9 and a movable piston expansion abutment orpeg 20, respectively. tationary arm I1 is of rigid construction and issecurely mounted, by means of two bolts 2|, to the bottom surface of topI and projects horizontally forward through the left end of ahorizontally disposed oblong orifice 22 in front wall |2. Moving arm I8is the load arm of a long lever or carrier 24 mounted similarly to armH, but is pivotally connected to top H by means of bolt 23 whichthreadedly engages the underside of said top similarly to bolts 2|. Therear end of lever 24 has a nut 25 pivotally attached thereto, and thenut in turn is threadedly mounted on a transversely mounted screw 26.Screw 28 is trunnioned in side walls l4 and I5 and penetrates the latterto have a large hand wheel 21 affixed to the terminal thereof.Sufficient clearance 28 is provided, longitudinally with respect tolever 24, to allow for the arcuate travel of the rear end of said lever,so that the manual actuation of hand wheel 21 will result in the arm I8and peg 20 slowly and powerfully approaching or receding from arm l1 andpeg 29, depending upon the direction of rotation of the hand wheel.

It is, of course, apparent that other means of actuation of arm US maybe employed, such as hydraulic, or compound lever means, but the meansdescribed above have been found efficient and inexpensive.

The abutments or pegs l9 and 20 may be identical in construction andinterchangeable; hence a description of peg l9 will sufiice for both.The

posed slot. The face 65 is adapted to fit between the said vertical ribsor to distribute pressure over a sufficiently large area around thediagonal slot so that the skirt is not fractured. The curvature of face65 may be altered to coincide with the configuration of differentpistons, where advisable. Peg 62 is provided with a shank 60 which isinserted in the opening in the forward end of arm l8 and is secured withthe nut 6|. Pivot head 64' prevents the head 63 from slipping off whileshoulder 64 provides a smooth bearing surface in place of the upper faceof arm l8, so that the head 63 may readily rotate.

A clamping device 29 is used to hold the piston to the stationary peg l9before and after the piston is acted on by peg so that the piston willnot become displaced and in order that accurate I measurements may bemade before, during, and

working face 55 is plane, vertical, and trans,

versely disposed with relation to the principal direction of motion ofpeg 20. Face 55 is provided with a horizontal rabbet 56 at the loweredge thereof, and a horizontal groove 51. The purpose of thesedepressions is to permit horizontally disposed reinforcing ribs on theinternal surfaces of the piston skirt to fit therein so that theexpanding pressure maybe exerted against the relatively smooth portionsof the cylindrical inner walls of the piston skirt. The placement ofthese depressions may be varied to suit the individual requirements ofdifferent types of pistons but the configuration shown in Figure 3 hasbeen found satisfactory for nearly all ordinary pistons. The inner face58 is provided with a deep rabbet 59, preferably curved at 59 so thatthe strain is evenly distributed and the likelihood of breakage isreduced. An integral shank fill threaded adjacent the end thereof,penetrates a vertically disposed orifice in arm iii and a nut 6| whentightened down securely clamps the peg L9 in place. Peg 20 is similarlyattached to the arm I8.

In Figures 4 and 5 there is illustrated an alternate type of 63 whichisadapted and the working face to swivel about the pivot 64 65 has acylindrically shaped surface. The peg 62 is substituted in place of peg20 when the piston skirt is of a type having vertically disposedreinforcing ribs, or when the piston skirt is provided with a diagonallydispeg. This peg 62 has a working head after the stretching or expandingoperation. This device 29 comprises a support arm 30, and a clampingface plate3l. Since the piston is comparatively light and the pegs I9and 20 maintain it in place while the piston is being expanded, theclamping device need notexert very great pressure. The face plate 3| issupported by an integral rod 32 perpendicularly projecting from the rearthereof to penetrate'the forward end of Support arm 30, and terminate inthe operating knob 33. A spiral expansive spring 34 serves to force theface plate 3| against the piston skirt and clamp it against peg I9. Thesupport arm 30 is adjustablyclamped at the rear end thereof to arm l1 bymeans of the thumb-screw 35. The forward portion of arm 30 is offset sothat a sufficient clearance is provided for the insertion of the piston.skirt and the operation of the face plate 3L A measuring device 36 isprovided for readily and accurately determining the amount of expansiongiven the piston skirt. Such a device orifice in the forward end of arm4| and is adjustably clamped by a thumb-nut 43; and the lower one ofwhich penetrates an orifice in the rear end of arm 44 and is adjustablyclamped by a thumb-nut 45. The forward end of arm 44 is adjustably andpivotally connected to the, micrometer by the integral threaded shank 46depending from said micrometer which penetrates said arm and is clampedby thumb-nut 41. Wherever desirable, the spacer 42 may be madeadjustable, or other suitable mechanism may be utilized for varying theeffective height of the micrometer.

An adjustable work table 48 is vertically regulable for supportingpistons of different heights and is pivotally mounted in a horizontalplane so that it may be swung into and out of position as needed. Thehorizontal face 49 is supported by an integral vertical post 50 which isin turn clamped in the bifurcated end of an arm 5|, the rear end ofwhich is pivotally mounted on an inverted L shaped bracket 52 aflixed tothe front wall l2. Actuation of thumb-screw 53 allows ad-z justment in ahorizontal plane and actuation of of the alignment of thepiston-engaging surfaces of the pegs may be made by operation of eitherone or both of the screws 9 and 120% I These adJustmentsare particularlyconvenient and important when the apparatus is used for expandingpistons of various designs.- I have found that the inner surfaces of theskirts of different types and makes of pistons taper axially of thepistons to varying degrees. The adjustments provided as described abovemake it possible to expand various kinds of pistons without providingspecial abutments for each particular design of piston.

In accordance with the invention, the embodiment disclosed in Figures 7to ll inclusive also is provided with an indicator gauge or the like formeasuring or indicating the amount of stretching or expansion of thepiston being worked upon. As shown. a dial gauge III having a feeler I2!is mounted upon a screw I22 having threaded engagement with a bracketI23 l secured to the frame by means of a screw Ill.

A lock nut I25 on the screw I24 serves to clamp the bracket I 23 inadjusted position, and a lock nut I26 on the screw I22 serves to clampthe screw and hence the gauge in adjusted position with respect to thebracket. The gauge body thus is so mounted as to be adjustable relativeto the frame. In use, the gauge is adjusted or moved to suchposition'that the feeler l2! engages the outer surface of a piston skirtprior to expanding thereof. Then the screw H3 is rotated to move thecross,headto the right so as to eflect relative separating movement ofthe abutments and stretching of thepiston until the gauge indicates thatthe predetermined desired amount of stretching has taken place.

Operation (of the form shown in Figures 7 to 11 inclusive) movable arm,

is to operate the screw 8 so asto move the cross head and abutment pegl2. :toward the left untilthe distance between the outer faces of thepegs It! and MI is considerably less than the inside diameter of thepiston skirt. The piston: is then placed over the pegs, and, if it isfound that the outer faces of the D88 Portions lleaand mi 'do notalignwith the associated inner piston skirt portions, the necessaryadjustments of one or both of the pegs. are effected in the manneralready described. The gauge is then set so that the 'feeler l2" engagesthe outer surface of the piston. and the screw is rotated in theopposite direction until the gauge shows that the proper amount ofstretching has taken place. Thereafter the screw is again rotated tomove the cross head to the left so that the. piston may be removed fromthe apparatus.

The apparatus shown herein embody the invention in preferred andcommercially successful forms, but it is to be understood that. changesmay be made without departing from the invention as defined in theclaim.

I claim: d A piston skirt expanding machine including a stationarycasing; an arm fixedly attached to said casing; a movable arm attachedto said casing and adapted for movement toward and away from saidstationary am, saidmovement being rectilinear in at least one plane; apair of pegs for coal-B n! he inside surface of a piston skirt, saidpegs being-mounted one on each arm; and a measuring device having afeeler movable in substantially the same direction as the said devicebeing adjustably mounted on said casing whereby the same may be rigidlypositioned. so that the feeler may contest the outside of said pistonskirt adjacent the peg of the movable arm, and register the amount ofmovement in said skirt portion in said plane, caused by the peg on themovable arm.

DAVID RUBIN.

